1. Field of the Invention
The present invention relates to a thermal transfer printer capable of simply and quickly printing a thermal transfer image of an excellent image quality without using any feed core when a roll of thermal transfer recording web (hereinafter referred to as xe2x80x9cthermal transfer recording web rollxe2x80x9d) is loaded into a thermal transfer printer, a thermal transfer recording method and a thermal transfer recording web roll.
2. Description of the Related Art
Various known thermal transfer recording methods use a thermal transfer sheet having a base sheet and a color transfer layer formed on the base sheet, and prints an image of a character, a figure or a pattern on a recording sheet by heating portions of the transfer color layer from behind with a thermal head or the like to transfer portions of the color transfer layer corresponding to yellow, magenta and cyan parts of the image to the recording sheet.
Known thermal transfer recording methods are classified by the type of the color transfer layer into thermal sublimation transfer recording methods and thermal melting transfer recording methods. The thermal sublimation transfer recording method uses a thermal transfer sheet formed by coating a base sheet with a transfer color layer of a binder containing sublimable dyes, heats the thermal transfer sheet from behind the same to sublimate and transfer the dyes contained in the transfer color layer to a recording sheet. The recording surface of the recording sheet is coated with a dye-recipient layer.
The thermal melting transfer recording method uses a thermal transfer sheet formed by coating a base sheet with a transfer color layer capable of being readily softened and melted by heating and of being transferred, and transfers portions of the transfer color layer to a recording sheet by heating the thermal transfer sheet from behind the same.
Both the thermal sublimation transfer recording method and the thermal melting transfer recording method are capable of forming both monochromatic images and multicolor images. The thermal transfer recording method uses a three color thermal transfer sheet to print images in three colors, i.e., yellow, magenta and cyan, or a four-color thermal transfer sheet to print images in four colors, i.e., yellow, magenta, cyan and black, and records color images on recording sheets by transferring portions of the thermal transfer sheet corresponding to parts of those colors of images to recording sheets.
The thermal transfer recording method uses thermal transfer recording sheets, i.e., recording sheets, and feeds the thermal transfer recording sheets in a stack to a printer or uses a recording web and feeds the recording web in a recording web roll to a printer.
The thermal transfer printing is applied prevalently to mass printing in recent years and rolled thermal transfer recording webs are used prevalently. Generally, the thermal transfer recording web is wound in a roll on a feed core, i.e., a feed bobbin, the leading edge of the thermal transfer recording web is attached adhesively to a take up core, i.e., a take up bobbin, to take up the thermal transfer recording web on the takeup core or portions of the thermal transfer recording web used for thermal transfer printing are cut and discharged in sheets. The rolled thermal transfer web needs a feed core. The feed core is scrapped or reused after the rolled thermal transfer recording web has been exhausted. The core must be formed in a high dimensional accuracy to roll the thermal transfer web thereon uniformly without creasing the same and hence the core is costly.
The core of a rolled thermal transfer recording web comes into contact with the members of a driving unit of a printer when the roll of the thermal transfer recording web is rotated in the printer. Therefore, when a paper tube made principally of paper pulp and less expensive than a plastic tube is used to reduce printing cost, the paper tube is abraded frictionally by the members of the driving unit into paper powder, the paper powder is scattered in the printer, and forms pinholes that reduces image quality in printed matters produced by thermal transfer printing.
Time and effort are required for purchasing and storing feed cores, loading the same to a takeup mechanism and taking up the thermal transfer recording web.
The present invention has been made in view of such problems and it is therefore an object of the present invention to provide a printer capable of simply and quickly printing a thermal transfer image of an excellent image quality without using any feed core when a roll of thermal transfer recording web is loaded into a thermal transfer printer, a thermal transfer recording method and a thermal transfer recording web roll.
According to the present invention, a thermal transfer printer includes: a thermal transfer recording web roll having a bore and obtained by rolling a thermal transfer web, in which a segment of the thermal transfer recording web forming an innermost layer of the thermal transfer recording web roll is fixed to a part of a segment of the same forming a second innermost layer of the thermal transfer recording web roll;
a rotative driving mechanism inserted in the bore of the thermal transfer recording web roll; and
a thermal transfer recording unit for recording images on the thermal transfer recording web unwound from the thermal transfer recording web roll held by the rotative driving mechanism.
In the thermal transfer printer according to the present invention, the segment of the innermost layer of the thermal transfer recording web roll excluding an inner edge part is fixed to the part of the second inner most layer, and the rotative driving mechanism includes a holding device for holding the inner edge part of the thermal transfer recording web.
In the thermal transfer printer according to the present invention, the holding device has a holding rod having a diameter substantially equal to that of the bore of the thermal transfer recording web roll, and having in its circumference with a recess for holding the inner edge part of the thermal transfer recording web.
In the thermal transfer printer according to the present invention, the holding device has a holding rod having a diameter substantially equal to that of the bore of the thermal transfer recording web roll, and having a groove to receive the inner edge part of the thermal transfer recording web.
In the thermal transfer printer according to the present invention, the holding device is provided with a pair of drive shafts for holding the inner edge part of the thermal transfer recording web.
In the thermal transfer printer according to the present invention, the rotative driving mechanism includes a pair of caps disposed on opposite end surfaces of the thermal transfer recording web roll, respectively, so as to be engaged in the bore of the thermal transfer recording web roll.
In the thermal transfer printer according to the present invention, at least one of the caps has elastic parts for applying pressure radially outward to an inner surface of the bore of the thermal transfer recording web roll.
In the thermal transfer printer according to the present invention, at least one of the caps has a flange in contact with the end surface of the thermal transfer recording web roll.
In the thermal transfer printer according to the present invention, one of the caps has elastic parts for applying pressure radially outward to an inner surface of the bore of the thermal transfer recording web roll, and the other cap has a part to be inserted into the former cap to press the elastic parts radially outward.
In the thermal transfer printer according to the present invention, each of the pair of caps is held in the bore of the thermal transfer recording web roll through a bushing provided with a slit.
In the thermal transfer printer according to the present invention, a slit is formed between the adjacent elastic parts of the cap.
In the thermal transfer printer according to the present invention, the segment of the inner end segment of the rolled thermal transfer recording web roll excluding an inner edge part is fixed to the part of the second innermost layer, and the inner edge part is inserted in the slit formed in the bushing or the slit of the cap.
In the thermal transfer printer according to the present invention, the rotative driving mechanism includes drive rollers disposed in the bore of the thermal transfer recording web roll in contact with an inner surface of the bore of the thermal transfer recording web roll.
In the thermal transfer printer according to the present invention, the rotative driving mechanism includes a pair of drive rollers, and the center distance between the pair of drive rollers is adjustable.
In the thermal transfer printer according to the present invention, the pair of drive rollers are biased away from each other.
In the thermal transfer printer according to the present invention, the drive rollers have a circumference provided with ridges or knobs.
In the thermal transfer printer according to the present invention, the rotative driving mechanism includes a plurality of drive rollers disposed in the bore of the thermal transfer recording web roll, and an endless belt extended around the plurality of drive rollers and pressed by the plurality of drive rollers so as to be in contact with an inner surface of the bore of the thermal transfer recording web roll.
In the thermal transfer printer according to the present invention, the rotative driving mechanism includes a pair of rotative driving members disposed at opposite end surfaces of the thermal transfer recording web roll and capable of applying pressure to the opposite end surfaces of the thermal transfer recording web roll.
In the thermal transfer printer according to the present invention, the pair of rotative driving members have taper side surfaces tapering toward the end surfaces of the thermal transfer recording web roll, respectively.
In the thermal transfer printer according to the present invention, the pair of rotative driving members are mounted on a center shaft inserted in the bore of the thermal transfer recording web roll.
In the thermal transfer printer according to the present invention, at least one of the pair of rotative driving members is pressed by a spring mounted on the center shaft against the end surface of the thermal transfer recording web roll.
In the thermal transfer printer according to the present invention, distance between the rotative driving members mounted on the center shaft is adjustable.
According to the present invention, a thermal transfer recording method includes the steps of: preparing a thermal transfer recording web roll having a bore and obtained by rolling a thermal transfer web, in which a segment of the thermal transfer recording web forming an innermost layer of the thermal transfer recording web roll is fixed to a part of a segment of the same forming a second innermost layer of the thermal transfer recording web roll; unwinding the thermal transfer recording web by engaging a rotative driving mechanism in the bore of the thermal transfer recording web roll and rotating the thermal transfer recording web roll by the rotative driving mechanism; and carrying out a thermal transfer recording operation to record an image on the thermal transfer recording web unwound from the thermal transfer recording web roll.
In the thermal transfer recording method according to the present invention, the segment of the innermost layer of the rolled thermal transfer recording web roll excluding an inner edge part is fixed to a part of the second innermost layer, and the thermal transfer recording web roll is driven for rotation by the rotative driving mechanism including a holding device holding the inner edge part of the thermal transfer recording web.
In the thermal transfer recording method according to the present invention, the rotative driving mechanism includes a pair of caps disposed at opposite end surfaces of the thermal transfer recording web roll, respectively, so as to be engaged in the bore of the thermal transfer recording web roll.
In the thermal transfer recording method according to the present invention, the rotative driving mechanism includes drive rollers disposed in the bore of the thermal transfer recording web roll in contact with an inner surface of the bore of the thermal transfer recording web roll.
In the thermal transfer recording method according to the present invention, the rotative driving mechanism includes a pair of rotative driving members disposed at opposite end surfaces of the thermal transfer recording web roll, respectively, and capable of applying pressure to the end surfaces of the thermal transfer recording web roll.
According to the present invention, a thermal transfer recording web roll to be used for a thermal transfer printer, has a bore, and is formed for rolling a thermal transfer recording web; wherein a segment of the thermal transfer recording web forming the innermost layer of the thermal transfer recording web roll is fixed to a part of a segment of the thermal transfer recording web forming the second innermost layer of the thermal transfer recording web roll.
In the thermal transfer recording web roll according to the present invention, the segment of the innermost layer of the thermal transfer recording web roll excluding an inner edge part is fixed to the second innermost layer of the thermal transfer recording web roll.
According to the present invention, the thermal transfer recording web roll does not need any feed core, is inexpensive, can be prepared without requiring time and effort, and is capable of recording a thermal transfer image in a satisfactory image quality.
According to the present invention, the segment of the innermost layer of the thermal transfer recording web roll, excluding an inner end part, of the thermal transfer recording web roll is fixed to the part of the second innermost layer, and the rotative driving mechanism includes a pair of flanged tubular shafts each having a tubular part provided with a slit.
According to the present invention, the tubular part of one of the flanged tubular shaft is inserted into the tubular part of the other flanged tubular shaft.
According to the present invention, the pair of flanged tubular shafts are driven individually by separate driving mechanisms, respectively.
According to the present invention, one of the flanged tubular shafts is provided with a central rod connected to the other flanged shaft.
According to the present invention, the pair of flanged tubular shafts are supported for rotation by support members, respectively.
According to the present invention, the thermal transfer recording method uses a thermal transfer recording web roll in which the segment of the innermost layer of the thermal transfer web roll excluding an inner end part, is fixed to the part of the second innermost layer, and the thermal transfer web roll is driven for rotation by the rotative driving mechanism including a pair of flanged tubular shafts each having a tubular part provided with a slit.